How long to image the Trifid Nebula with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 4 h 39 min (4,184 subs of 4 s) for a solid image of the Trifid Nebula. A quick look takes 1 h 10 min; a showpiece 19 h. Under a Bortle 3 rural sky the solid figure drops to 3 h 07 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 83% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 45 min669 subs | 2 h 58 min2,675 subs | 12 h10,699 subs |
| Bortle 2Typical dark site | 45 min681 subs | 3 h 01 min2,722 subs | 12 h10,885 subs |
| Bortle 3Rural | 47 min703 subs | 3 h 07 min2,809 subs | 12 h11,235 subs |
| Bortle 4Rural / suburban transition | 50 min756 subs | 3 h 21 min3,022 subs | 13 h12,085 subs |
| Bortle 5Suburban | 56 min840 subs | 3 h 44 min3,358 subs | 15 h13,431 subs |
| Bortle 6Bright suburban | 1 h 10 min1,046 subs | 4 h 39 min4,184 subs | 19 h16,735 subs |
| Bortle 7Suburban / urban transition | 1 h 36 min1,440 subs | 6 h 24 min5,758 subs | 26 h23,030 subs |
| Bortle 8City | 2 h 17 min2,051 subs | 9 h 07 min8,201 subs | 36 h32,803 subs |
| Bortle 9Inner city | 3 h 44 min3,353 subs | 15 h13,412 subs | 60 h53,648 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 6 h 03 min of run time. The Odyssey’s battery is rated at about 5 h, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time.)
- USB power bank 20000mAh 5V 2.4AUnistellar says plain 5 V 2.4 A and warns against fast or adaptive chargers.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.
Everything that fits the Odyssey →
How it frames
The Trifid Nebula is 28′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 83% of the frame’s short side.
Filters
The Trifid Nebula is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the Odyssey has no dual-band option: No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey. The figures above are for the No filter position, and a darker sky is the lever that remains.
About the Trifid Nebula
Red emission, blue reflection and dark lanes in one object. Shoot it without a filter to keep the blue, or dual-band for the red.
M20, NGC 6514 · Emission nebula in Sagittarius · magnitude 6.3 · 28′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
About the Unistellar Odyssey
Unistellar’s compact 85 mm with autofocus and tiny pixels. Sharp, but the fine sampling costs time on faint extended targets. The Odyssey Pro is the same telescope with an eyepiece added, so these figures apply to both.
Fixed 4 s subs in Enhanced Vision; they cannot be changed. No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey.
The Odyssey uses fixed 4 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.
Stack across nights. Every smart scope app can continue a stack or you can combine the saved frames on a computer; the figures here are totals, not single-session limits.
Have an image of the Trifid Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Trifid Nebula with the ZWO Seestar S50: 44 min from Bortle 6
- Trifid Nebula with the ZWO Seestar S50 Pro: 49 min from Bortle 6
- Trifid Nebula with the ZWO Seestar S30: 51 min from Bortle 6
- Trifid Nebula with the ZWO Seestar S30 Pro: 53 min from Bortle 6
- Trifid Nebula with the DwarfLab DWARF 3: 55 min from Bortle 6
- Trifid Nebula with the DwarfLab DWARF mini: 43 min from Bortle 6
- Trifid Nebula with the DwarfLab Draco: 35 min from Bortle 6
- Trifid Nebula with the DwarfLab DWARF II: 3 h 48 min from Bortle 6
- Trifid Nebula with the Vaonis Vespera II: 1 h 07 min from Bortle 6
- Trifid Nebula with the Vaonis Vespera Pro: 2 h 30 min from Bortle 6
- Trifid Nebula with the Vaonis Vespera 3: 1 h 04 min from Bortle 6
- Trifid Nebula with the Vaonis Vespera Pro 2: 2 h 23 min from Bortle 6
- Trifid Nebula with the Unistellar eQuinox 2: 1 h from Bortle 6
- Trifid Nebula with the Celestron Origin: 18 min from Bortle 6
- Trifid Nebula with the Celestron Origin Mark II: 24 min from Bortle 6
All telescopes for the Trifid Nebula · All targets for the Odyssey